Discovering Computers Fundamentals Fifth Edition Chapter 8 Communications and Networks.

Discovering Computers

FundamentalsFifth Edition

Chapter 8 Communicati

ons and Networks

Chapter 8 Objectives

Discuss the components required for successful communications

Discuss the components required for successful communications

Describe uses of computer communicationsDescribe uses of computer communications

Differentiate among types of networksDifferentiate among types of networks

Explain the purpose ofcommunications software

Explain the purpose ofcommunications software

Describe various types of lines for communications over the telephone network

Describe various types of lines for communications over the telephone network

Describe commonly usedcommunications devices

Describe commonly usedcommunications devices

Discuss different ways to set upa home network

Discuss different ways to set upa home network

Identify various physical and wireless transmission media

Identify various physical and wireless transmission media

Next

Communications

What are computer communications?

Nextp. 296 - 297 Fig. 8-1

Sending device — initiates

instruction to transmit data, instructions, or

information

What is needed for successful communications?

Communications

Nextp. 296

Communications device — connects the communications

channel to the receiving device

Receiving device — accepts

transmission of data, instructions, or

information

Communications device — connects

the sending device to the communications

channel

Communications channel — media

on which data, instructions, or

information travel

Uses of Computer CommunicationsWhat are some uses of communications technology?

Nextp. 298

Internet Web E-Mail Instant Messaging

Chat Rooms Newsgroups Blogs Wikis

RSS VoIP FTP Web Folders

Video Conferencing

Fax Machine or Computer Fax/Modem

Uses of Computer CommunicationsWhat are wireless messaging services?

p. 298 - 299 Next

Wireless instant messaging allows wireless mobile

devices to exchange messages

Text messagingallows users to send

and receive short text messages on a phone

or other mobile device Picture/video messaging

allows users to send graphics, pictures, video

clips, sound files, and short text messagesClick to view Web Link,

click Chapter 8, Click Web Linkfrom left navigation, then click Video Messaging below Chapter 8

http://www.scsite.com/dcf5ecp/ch8/weblink/

Uses of Computer CommunicationsWhat are wireless Internet access points and cybercafés?

Nextp. 300 -301 Fig. 8-4

Wireless Internet access point allows wireless connection to Internet in public location

Cybercafé is a coffee house that provides computers with Internet access

Uses of Computer CommunicationsWhat is a global positioning system (GPS)?

Nextp. 301 Fig. 8-5

Step 1.GPS satellites orbit Earth. Every thousandth of a second, each satellite sends a signal that indicates its current position to the GPS receiver.

Step 2.A GPS receiver (such as in a car, a wearable device, a smart phone, a handheld device, or a collar) determines its location on Earth by analyzing at least 3 separate satellite signals from the 24 satellites in orbit.

Click to view Web Link,click Chapter 8, Click Web Linkfrom left navigation, then click GPS below Chapter 8


Uses of Computer CommunicationsWhat are collaboration and groupware?

Nextp. 302 Fig. 8-6

Web conference A document

management system provides for storage and management of a company’s documents

Groupware is softwarethat allows peopleto shareinformation

Collaboration is working with other users connected to a server

Click to view Web Link,click Chapter 8, Click Web Linkfrom left navigation, then click Web Conferencesbelow Chapter 8


Networks

What is a network?

Nextp. 303 - 304

Collection of computers and devices connected via communications devices and transmissionmedia

What is a local area network (LAN)? Network in limited geographical area such

as home or office building Metropolitan area network (MAN) connects

LANs in city or town

Networks

What is a wide area network (WAN)?

Nextp. 304 Fig. 8-8

Network that covers large geographic area using many types of media

Internet is world’s largest WAN

Networks

What is a client/server network?

Nextp. 305 Fig. 8-9

One or more computers act as server and other computers, or clients, access server

Networks

What is a peer-to-peer network?

Nextp. 305 Fig. 8-10

Simple network that connects fewer than 10 computers

Each computer, or peer, has equal capabilities

Networks

What is Internet peer-to-peer (P2P)?


Enables users to connect to each other’s hard disks and exchange files directly

Networks

What is network topology? Layout of devices in a network

Popular topologies are bus, ring, and star Bus network

All computers and devices connect to a single central cable, or bus


Networks

What is a ring network?


Cable forms closed loop (ring) with all computers and devices arranged along ring

Data travels from device to device around entire ring, in one direction

Networks

What is a star network?


All devices connect to a central device (hub or switch)

All data transferred from one computer to another passes through hub or switch

Networks

What is an intranet?

Nextp. 307

Extranet allows customers or suppliers to access

part of company’s intranet

Typically includes connection to Internet

Makes information accessible to employees

Internal network that uses Internet technologies

Networks

What are Ethernet and token ring?

Nextp. 308

Ethernet technology allows computers to contend for access to network

If two computers send data at same time, a collision occurs and computers must send again

Token ring technology controls access to network by requiring devices to pass a special signal, called tokenClick to view Web Link,

click Chapter 8, Click Web Link from left navigation, then click Ethernet below Chapter 8


Networks

What are TCP/IP and 802.11 (Wi-Fi)?

Nextp. 308 - 309

TCP/IP (Transmission Control Protocol/Internet Protocol) technology transmits data by breaking it up into small pieces, or packets Commonly used for Internet transmissions

802.11 is a family of standards for wireless LANs Also known as Wi-Fi (wireless fidelity)

What is Bluetooth? Short-range radio waves transmit

data between Bluetooth devices

Communications Software

What is communications software?

Nextp. 310

Programs that help users establish connection to Internet, other network, or another computer Programs that help users

manage transmission of data, instructions, and information

Programs that provide an interface for users to communicate with one another

Communications Over the Telephone Network

What is a dial-up line?

Nextp. 311

Temporary connection using one or more analog telephone lines for communications Costs no more than making regular call Computers at any two locations can establish a

connection using modems and telephone network

Communications Over the Telephone Network

What is a dedicated line?


Five types are ISDN line, DSL, FTTP, T-carrier line, and ATM

Always-on connection between two communications devices

Communications Devices

What is a communications device?

Nextp. 312 – 313 Fig. 8-17

Any type of hardware capable of transmittingdata, instructions, and information between

devices


What is a dial-up modem?

Nextp. 313

Converts digital signals to analog signals and vice versa A modem usually is in the form of an adapter card that you

insert in an expansion slot on a motherboard


What are ISDN and DSL modems?

Nextp. 314

Communications devices that send and receive digital ISDN and DSL signals

Communications devices that send and receive digital ISDN and DSL signals

Usually external devices in which one end connects to a telephone line and the other

end connects to a port on the system unit

Usually external devices in which one end connects to a telephone line and the other

end connects to a port on the system unit


What is a cable modem?


Sends and receives data over cable television network

Much faster than dial-up modem or ISDN

Click to view Web Link,click Chapter 8, Click Web Linkfrom left navigation, then click Cable Modems below Chapter 8



What is a wireless modem?


Allows access to the Internet wirelessly from a notebook computer, a smart phone, or other mobile device

Typically use the same waves used by cellular telephones


What is a network card?


Adapter card, PC Card, ExpressCard module, USB network adapter or flash card that enables a computer or device to access a network


What is a router?


Connects computers and transmits data to correct destination on network

Routers forward data on the Internet using fastest available path

Home Networks

What is a home network?

Nextp. 316 - 317 Fig. 8-22

Multiple computers connected in home

Several types of home networks Ethernet — connect

computers via cable Powerline cable —

use electrical lines in house Phoneline — use telephone

lines

Click to view Web Link,click Chapter 8, Click Web Linkfrom left navigation, then click Home Networks below Chapter 8


Communications Channel

What is a communications channel?

Nextp. 317

Transmission media on which data, instructions, or information travel in communications system

Bandwidth is amount of data that can travel over a communications channel

Transmission media are materials capable of carrying one or more signals

Physical Transmission Media

What are twisted-pair cable and coaxial cable?

Nextp. 319 - 320 Figs. 8-24—8-25

Twisted-pair cable is used for telephone systems and network cabling Coaxial cable is often used for cable television wiring

Physical Transmission Media

What is fiber-optic cable?


Capable of carrying significantly more data at faster speeds than wire cables

Less susceptible to interference (noise) and, therefore, more secure

Smaller size (thinner and lighter)

Wireless Transmission Media

What is wireless transmission media?

Nextp. 320

Used when inconvenient, impractical, or impossible to install cables

Includes infrared, broadcast radio, cellular radio, microwaves, and communications satellites

Why use a network?

Easily share files and data Share resources such as printers and Internet

connections Communicate with other network users (e-mail,

instant messaging, video-conferencing, etc.) Store data centrally (using a file server) for ease of

access and back-up Keep all of our settings centrally so we can use any

workstation

Why not use a network?

The computer is vulnerable to hackers If the network breaks, many tasks become very

difficult Your computer can more easily be attacked by a

virus We have to be careful about revealing personal

information We have to be careful to avoid suspect websites that

might contain malware We have to be aware that information found on The

Internet is not always accurate or reliable

Summary of Communications and Networks

Chapter 8 Complete

Communications terminology and applications

Communications terminology and applications

How to join computers into a networkHow to join computers into a network

Various communications devices, media, and procedures

Various communications devices, media, and procedures

Discovering Computers Fundamentals Fifth Edition Chapter 8 Communications and Networks.

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